1. Field of Invention
The present invention relates to a wheelbarrow which is also equipped with an engine and a drive mechanism which are capable of propelling the wheelbarrow.
2. The Prior Art
The usefulness of various types of wheelbarrows and carts in allowing a man to transport a load are well known in the art. Single wheeled wheelbarrows have been found to be particularly useful in a variety of particular settings. Typically, while in use, the wheelbarrow's load is balanced over the wheel. As a result, the user of the wheelbarrow is not required to bear the weight of the entire load. The load, rather, is merely lifted until its weight pivots over the wheel sufficiently to place a substantial amount of the weight on the wheel. At this point the load can be pushed forward without the requirement of also lifting the entire load.
Single wheeled wheelbarrows are particularly useful in transporting a small but heavy load. The single wheel allows the load to be transported over a surface which is wide enough to accommodate the one wheel. As a result, on rough or soft terrain, a very narrow strip of passable surface is required. In the construction industry, for example, it is common to place a thin strip of lumber on soft or wet ground in order to roll wheelbarrows to a desired location. Problems, however, are encountered when an attempt is made to wheel a wheelbarrow over a surface which is not solid enough to support the weight of the load. In such a situation the wheelbarrow may become mired in mud or other material, and since the user is very often transporting loads which tax the limits of his strength, it is possible that the load will be upset and lost and injury may even result. In the alternative, it may take the efforts of several workmen together with ropes or pulleys to move the load.
Similar situations may be encountered in attempting to transport loads over rough terrain. While using a wheelbarrow in construction, gardening and other similar areas it is often necessary to cross terrain which is uneven or which is covered with debris of various types. Indeed the wheelbarrow is often particularly useful in moving loads across terrain which is virtually impassable by other larger particles such as between trees and through narrow gates. Again, however, if a user is pushing a heavy load and suddenly encounters an obstruction, such as a piece of construction debris, he may not have sufficient strength to push the load over or around the obstruction.
Several attempts have been made to solve the problems described above and to make the wheelbarrow easier to push by installing a source of locomotive power. Typically a gasoline engine has been mounted on the wheelbarrow in a manner which does not interfere with transporting a load. A drive means then is added which translates the power of the engine to the wheel of the wheelbarrow. The drive means used have typically been simple direct chain or belt drives which cause the wheelbarrow to be propelled forward when the engine is running.
Even though employing an engine allows the wheelbarrow to be more easily pushed forward under certain conditions, one major problem is that motorized wheelbarrows have generally only had a single forward gear. When the engine and drive train are engaged the wheelbarrow is thrust forward. One of the advantages of using a wheelbarrow, however, is its ability to be maneuvered in tight places which often requires the wheelbarrow to be pulled backward for a short distance before it can again move forward. Existing motorized wheelbarrows are of no help in performing such a maneuver and may even impede such a maneuver by the extra weight and bulk which has been added by the engine and drive train.
The addition of an engine to a wheelbarrow can defeat the balance which is achieved in conventional wheelbarrows. If the weight of the engine is placed too far to the rear, it may be difficult to lift the handles of the wheelbarrow sufficiently to balance the load, including the engine, over the front wheel. As a result, the user is forced to constantly lift the load putting a strain on various parts of his body, particularly his back.
The prior art has also identified the problem of motorized wheelbarrows stalling when the engine is engaged. Conventional clutch mechanisms have only been of minimal usefulness. When the conventional clutch is engaged the engine is immediately required to accelerate the heavy load along with the relatively heavy wheelbarrow. As a result, many times the engine stalls leaving the load stationary. It is difficult to ease the engine into gear and thus gradually accelerate the wheelbarrow.
Existing motorized wheelbarrows have also failed to deal adequately with the problem of becoming stuck in soft muddy ground and being stopped by obstacles in their path. Generally, motorized wheelbarrows are simply conventional wheelbarrows with minimal modifications. For example, the tire of a typical wheelbarrow is not a drive wheel and generally has a smooth tread. Motorized wheelbarrows have also used a similar tire. The result is that existing motorized wheelbarrows are very likely to become stuck when crossing soft ground because of the added weight of the drive mechanism and because of the lack of an adequate tread.
A further serious problem with existing motorized wheelbarrows is the problem of emptying the load. Until now it has been the practice to dump a motorized wheelbarrow in the same manner as a conventional wheelbarrow. That is, the handles of the wheelbarrow are lifted upwardly until the wheelbarrow pivots over the wheel sufficiently to cause the load to fall out of the front of the wheelbarrow. Alternatively, the wheelbarrow may be tipped to one side or another until the load falls out of the wheelbarrow.
The problems with emptying the wheelbarrow in the conventional manner are apparent. One problem is that the user is required to lift both the load and the engine in order to empty the wheelbarrow. This may be difficult, especially when the wheelbarrow contains a very heavy load. In addition, tilting a gasoline engine approximately 90 degrees is obviously undesirable. Gasoline may run out of the gas tank onto the hot engine causing serious safety problems and gasoline and oil may be allowed to flow into the carburetor causing the engine to flood or requiring the carburetor to be cleaned before further use. While certain motorized carts have included beds which pivot independently of the motor, the prior art does not diclose a motorized wheelbarrow where that is the case.
The result is that while it may be desirable to propel a wheelbarrow using an engine, no acceptable solution has been developed. Safety and related considerations may make it preferable that a workman have help in moving a heavy wheelbarrow over rough and wet terrain and up inclines, however, existing motorized wheelbarrows may simply add to the existing problems. The problems discussed above related to the direct drive of the device make this type of device difficult to use and maneuver. In addition, the fact that existing devices have no reverse gear further limits their usefulness. It is often desirable to backup a wheelbarrow a short distance in order to maneuver it around a corner or through a tight space. The lack of a reverse gear severely limits this capability. When these problems are added to the problem of emptying the wheelbarrow when the bed of the wheelbarrow is rigidly mounted to the frame, it is clear that improvements in the art are needed.
It is apparent that what is needed in the art is a motorized wheelbarrow which largely overcomes the problems presently encountered. It would be an advancement in the art to provide a motorized wheelbarrow with both a forward and a reverse gear and with a clutch mechanism which will allow the loaded wheelbarrow to begin moving gradually without causing the engine to stall. It would also be an advancement in the art if such a device could be emptied without tipping the entire wheelbarrow including the engine. It would also be an advancement in the art if such a wheelbarrow were well balanced and maneuverable and was not likely to become mired when crossing mud or other soft surfaces. Such a device is disclosed and claimed below.